Tuesday, August 5, 2008
Exhibit Hall CD, Midwest Airlines Center
Jeffrey M. Harrison1, Scott B. Williams1 and Laurel J. Anderson2, (1)Department of Botany/Microbiology, Ohio Wesleyan University, Delaware, OH, (2)Department of Botany and Microbiology, Ohio Wesleyan University, Delaware, OH
Background/Question/Methods Alliaria petiolata is an established invader of temperate forests in the Northeastern and Midwestern United States. This shade-tolerant biennial herb overwinters as a basal rosette and grows a flowering stalk in early spring. Little is known about the spatial invasion patterns of A. petiolata, and understanding these patterns could help identify microsites that facilitate the establishment of this species in uninvaded communities. It has been observed, but never quantified, that A. petiolata is often more abundant near the bases of trees. This study examined the spatial distribution of an A. petiolata population in a forested nature preserve near Delaware, Ohio. The goal was to determine if A. petiolata plants are randomly distributed across the forest floor or if there is a positive association between the invasive species and trees. A 40x50 meter plot was set up using tape measures as “X” and “Y” axes on a site with A. petiolata present. Each tree with a dbh of 5 cm or larger was given an X/Y coordinate value. A. petiolata plants were either grouped as a patch if there were two plants within 0.5 m of each other or treated as single plants, and each patch or individual was given a coordinate value. Spatial statistical analyses were performed on these coordinate points using the statistical software package “R”.
Results/Conclusions These data suggest that there is a significant, positive spatial association between A. petiolata and trees. Therefore, tree bases may provide key microhabitats for the initial invasion of A. petiolata into new sites. The mechanisms underlying this association are being investigated in ongoing studies.
